Our modern civilization cannot be sustained without burning carbonaceous materials for primarily motive and electrical power within the foreseeable future. The carbon dioxide (CO2) generated by such burning may be contributing to the gradual increase of the planet's temperature since 1900. This is occurring because CO2 permits the sun's energy to pass through the atmosphere but traps the longer wavelength energy radiated by the earth into the atmosphere.
The integrated plants and processes of this invention can help reduce the amount of CO2 currently vented into the air as a by-product of synthesizing the various products later discussed in the description of the manufacturing plant flow diagrams. Consequently, the reduction of CO2, which is a greenhouse gas, through the sequestration processes detailed herein, reduces the amount of greenhouse gases vented into the atmosphere. Further, the plants of this invention produce substantial energy savings by balancing exothermic and endothermic reactors as discussed below.
A variety of syngas generators are known, e.g., reformers, autothermal reactors, and gasifiers. Thus, U.S. Pat. No. 5,611,947 to J. S. Vavruska, U.S. Pat. No. 5,993,761 to Piotr and Albin Czernichowski and U.S. Pat. No. 6,153,852 to A. F. Blutke et al. all teach plasma reformers useful in constructing the integrated facilities used in the process of this invention. Likewise, Charles B. Benham et al., U.S. Pat. No. 5,621,155, utilize reformers to provide feedstreams to Fischer Tropsch reactors utilizing iron-based catalysts. U.S. Pat. No. 6,306,917 to Mark S. Bohn et al. teaches that hydrocarbons, carbon dioxide, and electric power can be manufactured at a plant using the Fischer-Tropsch (FT) reactors. It also suggests that urea can be produced from the carbon dioxide but no suggestion is given as to what facilities or processes are needed to manufacture the urea or the economic practicality of such a course.
The mentioned references deal with economic niches where tax incentives, regulatory penalties and other incentives must combine with other factors to make the processes commercial. A continuing increase in world temperatures or a firmer tie-in between the CO2 in the atmosphere and increasing world climate temperatures could quickly result in such incentives. The plants can be of particular utility when sited at remote locations where there is a large surplus of natural gas, petroleum, coal or other carbonaceous materials which are presently unrecoverable because of transportation costs, etc.
Increasing regulatory demands have limited, and, in some instances extinguished, the petroleum producers' and refiners' ability to flare waste gases. Further, there are often limitations on the amounts and kinds of other wastes that can be disposed of locally without harm to the environment, e.g., at an offshore crude oil producing platform. The multi-product plants of this invention provide a mechanism for packaging the various unit processes required for the utilization of this invention in a manner that the resulting plants can be utilized to supply electricity for a platform, eliminate the need for flares, convert the waste gases and liquids normally flared into liquid hydrocarbons, ammonia and/or urea while substantially eliminating local CO2 emissions. Solid commercial products can also be produced for agriculture, e.g., sulfur and urea prills. Such self-contained plants provide trade-offs; for offshore petroleum and/or natural gas platforms, which can improve their economic life span. This is particularly true where the deposits being recovered are sour or include some CO2 production.
The unit processes of this invention are each individually well known and the economics of the processes have been commercially proven. However, the joining of these unit processes as taught herein provides a utility for environmental and other purposes that has heretofore been unforeseen.